Screw on Lids have been used on food and drink containers for over 100 years, with screw threads being an effective way of giving a high sealing force between lid and container, usually sealed by an elastomer seal. However, a combination of factors cause contemporary containers to be more difficult to first open than ever. Sometimes the contents are sealed with an internal vacuum for more security, which increases the force necessary to unseal the container. Other containers have a security mechanism or other additional structure. To overcome these sealing, friction and vacuum forces, Jar and bottle lids often require users with significant strength and manual dexterity to break the grip of the seal and loosen the lid. Once the lid is initially loosened, the loose lid can easily be removed by hand. Jar and bottle openers which aid unscrewing tight lids by giving user extra grip and mechanical leverage on the lid date back to 1900 and prior. Of the various methods of gripping jars and Lids, an “Edlund” has been utilized in which one structure which is turned in one direction can be used to grip and rotate simultaneously. A central turning handle includes a pinion which operates a rack to compress around a lid. The same direction of turning of the handle which causes the members to compress around the lid also enable turning of the lid once the maximum compression for a non turning lid is achieved.
The use of this mechanism has also been accomplished using a force gradient across the height of a container in a device which holds the bottom of the container and the top of the container, possibly using two separate “Edlund” devices, or one “Edlund” device and a static holder. One of the problems with this arrangement is that such a device is significantly large and occupies significant shelf space, and it takes time to load and secure the container to be opened, and compressive forces at the bottom of the container can cause container damage and breakage in the case of a glass container. Containers are not necessarily weakest adjacent their bottom support surface. Further, the device has to be unloaded after the opening process has completed. The lack of ease of use from loading and unloading, as well as counter space occupation makes these devices ineffective.
What is needed is a product which will not occupy significant shelf space, which is small, portable and will not subject containers to opening forces across the height of the container and which are simple to use. The needed device should not be wed to one size or configuration of container to be opened. The needed device should be cyclical and provide an automatic reset action after opening.